A former Macquarie banker cut off a female assistant’s ponytail and another took “upskirting” photos of a female colleague, according to shocking new claims about the investment bank’s toxic and predatory culture.

The allegations are set out in a 26-page letter by Macpherson Kelley Lawyers sent last week to Macquarie and the Australian Securities and Investments Commission pertaining to a separate and unrelated matter.

Macpherson Kelley Lawyers are representing the group of investors in a planned class action against Macquarie Group, accusing the bank of artificially inflating the price of a small mining company before a sudden collapse wiped out many of its investors.

However, the letter has subsequently thrust the bank’s alleged “alpha-male” culture into the spotlight. There is no suggestion the former employees who are the subject of the class action were involved in sexual harassment at the bank.

"That culture led to a workplace defined by behaviour such as rampant drug taking leading to reckless trading after lunches, sexist and chauvinistic behaviour including an adviser engaging in predatory behaviour towards a female staff member and Macquarie choosing not to terminate that adviser because of the amount of commission the adviser earned," the letter reads.

Fairfax Media reported former Macquarie employees told the publisher female desk assistants were “regularly preyed upon by several brokers, who were never held to account”.

The brokers involved in the allegations no longer worked at the bank but continued to work in the finance industry, the report said.

One source told the publisher about a particular incident when a stockbroker used scissors to cut off a desk assistant’s ponytail in 2013 then “put the hair on her desk, right in front of her”.

“She was so shocked she didn’t say anything, and really only started talking about it at the Christmas party about a month later,” the source said.

"Everyone was laughing about it, it was just a funny story to them. It was difficult to be a woman there and maintain a sense of respect. Particularly when no one had your back," said another former staffer.

While at least two staff reportedly complained about the attack to an office manager, no disciplinary action had been taken.

There are also accusations of a female staff member being secretly photographed by a male colleague on at least two occasions, including one incident of “upskirting”.

Formal disciplinary action was not taken on either occasion, Fairfax Media reported.

In a statement issued today, Macquarie Group said it treated all allegations of inappropriate or illegal behaviour with “the utmost seriousness”.

“The allegations made by the lawyers, which appear to be an attempt to solicit clients, lack any credible evidence or source,” the statement read.

“Importantly, we note that although this will be the fourth article on this matter, no litigation against Macquarie has commenced.

“None of the workplace behaviour allegations raised by Fairfax involve current staff. The allegations were either never previously put to Macquarie, or those that were made were reviewed and appropriate action taken.”

The statement added that Macquarie had overhauled its retail advisory business, which included appointing a new management team, new systems, controls and training and substantial financial investment.